This invention relates to a method and apparatus for removing oil used to lubricate a vertical turbine pump from the oil tube at or near the bottom line shaft bearing to be lubricated and before the oil can exit the oil tube through a relief port provided in the bowl assembly. In this way, lubricating oil is prevented from contacting the water to be pumped.
In a conventional water well, the well borehole is drilled down some distance into a water-bearing formation. A well screen for receiving water is then positioned within the water-bearing formation. A non-porous pump casing is attached to the well screen. The pump casing extends from the well screen to the discharge head at the well""s surface. The pump bowl assembly with impellers for lifting water is typically located just above the well screen in the pump column. In order to enter the bowl assembly and be pumped to the surface, water must enter the well through the well screen and then rise to the pump bowl.
When no water is being pumped from the well, water in the well stands at the static water level. When water is being pumped from the well, the water level is lowered to the pumping water level. At the pumping water level, the water level must still be high enough so that the pump bowl is submerged. A pump can only function properly so long as there is sufficient water to cover the pump bowl.
Oil used to lubricate the line shaft bearings is continuously dripped into the oil tube from an oil reservoir located on the pump head. The oil from the reservoir travels down the oil tube lubricating the line shaft bearings and exits through a relief port in the bowl assembly. When water rises into the bowl assembly from a well screen located below the bowl, oil from the relief port floats to the surface of the water in the pump column. Because the density of the lubricating oil is less than the density of the water, the oil forms a floating layer on top of the water outside the pump column and inside the well casing.
A problem has developed in many deep production wells in which the static water level has been lowered by several hundred feet. The decrease in static water level may be the result of several factors; however, continuous water mining in the area is generally considered to be the primary cause. When the static water level is lowered, the pump bowl assembly must also be lowered in order to gain sufficient submergence to operate the well. In order to gain the requisite submergence, the pump bowl must frequently be lowered into the well screen by adding pump column, oil tube shaft, and bowl stages. Sometimes the pump bowl must be lowered several hundred feet into the well screen. When the pump bowl assembly is lowered into the well screen, the water being pumped by the well no longer rises into the pump bowl through the pump column. Instead, when the pump bowl is positioned within the well screen, water enters the pump bowl from the bottom, top, and sides. When water enters the pump from above the bowl assembly, it creates a downward flow of water past the bowl assembly and into the pump intake at the bottom of the bowl assembly. Oil from the oil tube exiting through the relief ports is caught up in the downward flow of water passing the ports. Consequently, the oil becomes mixed into the water to be pumped when it joins the downward movement of water into the pump intake. The oil is then lifted along with the water to the surface by the pump""s impellers. As a result, the water produced by a well can become contaminated by the oil used to lubricate the line shaft bearings. The use of food grade oil to lubricate the pump creates particular problems as food grade oil provides an excellent medium for bacteria growth in water delivery systems and storage tanks.
The lubricating oil removal assembly of the present invention provides a means for intercepting the oil used to lubricate the line shaft bearings before the oil can enter the pump. In my invention, holes are provided in the oil tube below the bottom bearing to be lubricated and above the relief ports typically provided in the bowl assembly. An annular relief collar is then provided around the oil tube at the location of the holes. A drainage pipe allows oil to flow from the relief collar to a reservoir located on the outside of the column pipe. A pump located within the reservoir lifts oil from the reservoir, through a tube, and onto the surface for reuse or disposal. Thus, lubricating oil is prevented from ever coming into contact with the well water. In the preferred embodiment of the invention, the oil tube with holes and annular collar together with the associated drainage pipe, oil reservoir and pump are manufactured as separate component parts which are joined with the column pipe and oil tube of the existing prior art pump structure.